Accurate determination of moisture content in gaseous environment such as air is useful in a wide variety of situations. Convenient devices capable of such determination will find widespread commercial applications.
Although piezoelectricity has been known for a long time, early studies were confined to naturally-occurring inorganic piezoelectric crystalline materials such as quartz and tourmaline, and studies on artificially manufactured piezoelectric materials such as certain organic polymers have been a very recent development. Especially, studies on the effect of moisture on the piezoelectric properties of piezoelectric organic polymers have occurred only very recently.
The present invention is a novel application of thermally and chemically stable moisture-sensitive piezoelectric materials as a moisture sensor for determining the relative humidity of gaseous environment. The invention is especially useful in high temperature applications such as in food processing technology where moisture sensing and control at elevated temperatures are important for the quality control of the food products.